Interlocked
by beamwrites
Summary: Harry has a sister! My take on the sibling story, now with proper grammar and definitely no elemental magic. That's just wrong.
1. Prologue: First Comes The Lightning

"It's a boy!"

His birth cries rang through the air, swiftly followed by those of his sister.

"Here she comes-- watch the head-- what will you call them?"

Lily Potter is sweaty, tired but satisfied.

"James?" She called.

"Harry James Potter and Rose Joanna Potter," proclaimed James proudly.

\--

A flash of green down the corridor, and a dull thump sounded. Her husband was dead, and she was now the last line of defence between Him and her children.

The door crashed open, the hastily moved desk flying across the room.

"Not them, not them, please not them!"

"Stand aside, you silly girl . . . stand aside now."

"Not them, please no, take me, kill me instead—"

"This is my last warning—"

"Not them! Please . . . have mercy . . . have mercy. . . . Not them! Not them! Please— I'll do anything— "

"Stand aside. Stand aside, girl!"

He could have forced her away from the crib, but it seemed more prudent to ﬁnish them all.

Another flash of green, and Lily Potter slumped to the floor, dead.

\--

They stood up in their shared crib, eyes seeing but not comprehending, that their mother was dead, that their father was dead, that they would never laugh at their antics, never take pride in their Quidditch prowess--

He pondered. Which first, He thought. The boy, with his black hair and green eyes, or the girl, with the red hair and hazel eyes? The boy, He decided. Poetic, for the last of a once-great pureblood house, sullied by the Mudblood Evans girl, to die in chronological order.

He lifted his wand at the crib.

"Avada Kedavra."

And then all He felt was pain, pain, pain, rising in a haze, eating away at His body, and only the cries of two children orphaned forever, as the last sound He heard.

\--

Sirius arrived at Godric's Hollow in his flying motorbike, panic rising with every step he took, as he saw the house with the lights out, the gate open, the roof blown off.

"James! Lily! Harry! Rose!" He shouted as he ran towards the house, chanting repeatedly under his breath to please not be dead, please not be dead, oh God please not be dead--

His prayers were not answered.

At the end of the hallway, lay the body of his best friend. His glasses were askew, lying spread-eagled, face still and unlaughing as it had never been in life.

He held the body close, sobbing apologies.

But then he heard a cry, followed by another. He remembered Lily, and the children.

And he rushed up the stairs, hoping yet again to God that Lily was still alive, that Harry was unharmed, that Rose was fine.

His God was a cruel one.

At the foot of the shared crib lay Lily Potter, the wife of his best friend and one of his best friends too. She looked peaceful in death, hair fanning around her face like an angel, as serene as she was passionate, no, had been passionate.

He felt no grief this time. Only anger at Volde-fucking-mort, and hate at the stinking rat for selling them out, and self loathing for even suggesting the switch.

The coos of the children brought him out of his red mist. Oh James, he thought sadly as he stared at his dead friends' lookalikes.

"Pah! Pah! Up!" giggled Rose, lifting her arms towards Sirius. He obliged, rocking her gently, causing both the children to laugh happily. As Rose and Harry fell asleep, he gently placed her back down in the crib, and went off to exact revenge from Peter.

With a longing glance at the gently snoring children in the crib, he stormed away and out of the house, handing a bewildered and scared Hagrid the keys to his motorbike.

Only later, as he was laughing maniacally in the middle of the street with fire and screaming Muggles around him, did he suddenly remember he never said goodbye to James and Lily.

\--

Hagrid brought Albus Dumbledore confirmation of the deaths of his protégés. He wept gently when he was alone, with only Fawkes for company. As tears dripped down from his long, crooked nose, he wondered how Sirius could have betrayed his best friends, his godson and goddaughter, and everything he had ever thought he stood for.

His heart broke even further when he realized that he would have to place Harry and Rose with their Aunt Petunia. He remembered the young, wide-eyed girl begging to go to Hogwarts like her younger sister, and found it hard to reconcile that image with the skinny, bitter, magic-hating woman she had become. She would surely not treat the children very well, but it was the best option out of many bad options. Most pureblood families would be gagging to take in the Boy Who Lived and his sister, with Voldemort supporters at the forefront, waiting for a chance to avenge their fallen master. No, better to let the children grow up hurt, than to not have them grow up at all.

He wondered if he would grow to regret that decision, if his conscience would let him sleep at night.

And every time his tinkling instruments told him that one of the twins was hurt, he would wince, and his heart would ache.

\--

Petunia Dursley took pride in her normalcy, with a normal house, in a normal neighbourhood, with a normal husband with a respectable job and a normal son. So when she found two children on the front step early one November morning, she was understandably upset and furious.

She read the letter, expressionless. Thoughts ran through her head. Magic had taken her sister from her. She would not let it take her niece and nephew. She vowed to raise the children so that they wouldn't be like them, so that they would be normal.

Whatever it took.

\--

The little boy sobbed soundlessly in his bed at night, trying to hide his tears from his sister again.

It never worked.

"Did Dudley hit you again?"

"Yeah, he did."

She hugged him, and he hugged her back. No other words were needed. In the 6 years they had lived at No. 4 Privet Drive, this had become a regular occurence. He took the brunt of the hits, so that his sister would not be hurt. But they both knew that her heart bled every time he came home with a new bruise or break from "tripping" or "slipping".

At least they had a safe space here, in the smallest bedroom of No. 4. Vernon had often threatened to lock them into the cupboard under the stairs, and only the thought that they might suffocate and cause the police to be called in prevented him from doing so.

They held each other tighter, crying silent tears into each other's shoulders. Who else could they go to? They only had each other in the whole wide world.

\--

"Happy birthday, Harry."

"Happy birthday, Rose."

The Dursleys didn't celebrate their birthdays. After all, why would they be civil in the slightest to a pair of orphan freaks? Vernon and Petunia delighted in telling the tale of how their parents died in a drunken car crash, and how their parents were drunken, good for nothing layabouts. Inevitably, one of the childrens' tempers would fracture and cause weird things to happen. And just as inevitably, they would be locked in their room without meals, often accompanied by cries of, "Freaks!"

Oh, they never doubted the car crash story. After all, it made perfect sense. What they did doubt, however, was the fact that their parents were either drunkards or layabouts. They had faith that one day, they would know the truth about their parents.

And one day, they would revel in the unquestionable fact that their parents were upstanding members of society, that they were good people, that the Dursleys were wrong.

They would know that their parents were heroes.

\--

Years passed. Harry turned their teacher's hair blue, and Rose suddenly found herself with Harry on top of their primary school while running from Dudley and his gang. Each and every time, Vernon Dursley would lock them in their room, only occasionally remembering to bring them cold tinned soup.

As they reached the end of their sixth year of primary school, they despaired at the fact that they would be separated from each other in secondary school. Harry would be going to Stonewall High, the local comprehensive, while Rose would be sent even further away, to an all-girls prep. They took small comfort in the fact that as Dudley would be going to Smeltings, they would no longer have to deal with him and his gang during school hours.

All that changed on one fateful summer day.

\--

"Get the post, girl!"

"Yes, Uncle Vernon." _You bloody git_ , she added under her breath.

She sorted through the post as she walked back to the breakfast table, slowing as she recognized two letters addressed to her and Harry.

Ms. R. Potter

The Smallest Bedroom

4 Privet Drive

Little Whinging

Surrey

And

Mr. H. Potter

The Smallest Bedroom

4 Privet Drive

Little Whinging

Surrey

As she handed Harry his letter, Dudley noticed that they both had mail. His little piggy eyes narrowed as he remembered that they never got mail. And in snatching Rose's letter, he started a chain of events that would change all of their lives forever.

\--

"Well, this is terrible," thought Harry and Rose in tandem. After a wild goose-chase all over the country, they were now stuck on a hut in the middle of a sea in the middle of nowhere. The raging storm was just the icing on the cake.

Together, they counted down to their 11th birthday.

"3, 2, 1--"

A crash shook the little hut, waking all the residents. Vernon, clutching his rifle, aimed it haphazardly at the door.

Another crash. Then another, and another, and then the door came down, highlighting a giant of a man standing in the doorway.

"'Ello there!"

With his bushy beard and glinting, beetle-like eyes, the man struck an imposing figure, causing both Harry and Rose to shrink back in fear.

All that disappeared when he smiled, his face wrinkling up in a smile, the wild tangle of hair waving like a bush in the wind.

"Me name's Hagrid, and I'm the groundskeeper at Hogwarts School of Witchcraft and Wizardry, the same place yer mum and pa went ter."

"Hogwhat now?" asked Rose timidly.

"Wha-- DURSLEY!" exclaimed Hagrid. "How dare you not tell them about their parents?"

"You," said Uncle Vernon in a trembling voice, "will not corrupt these freaks! And I will not pay for them to go to some crackpot school with some crazy headmaster--"

Unfortunately for Dudley, Vernon had crossed a line of Hagridcs. With a sharp jab of his flowery pink umbrella, Dudley grew a pig's tail, with a rather fitting squeal for accompaniment.

"Never insult Dumbledore ter me face, Dursley. Get out!" said Hagrid menacingly.

As the Dursleys scrambled to run out of the hut, Hagrid resumed grinning at the twins, who were now also grinning widely.

"Now, go ter sleep, you two. We got a big day ahead of us in Diagon Alley."

\--

After a long trip through Diagon Alley, it finally came to the time to buy their wands. Harry, through some cosmic joke, got the brother wand to Voldemort's, and Rose just received a nice, normal, non evil-twin wand.

"Rosewood, dragon heartstring, 9 inches. Perfect for all-round casting."

Harry rolled his eyes at his sister's shenanigans as she waved her wand around like a madman.

"Settle down, you bloody lunatic!"

"Jealous that I got a normal wand, brother dear?"

This started a Potter tickle fight, and Potter tickle fights were legendary. Well, among themselves. They had no one else to talk to, you see.

They almost scared their Snowy Owl to death.

\--

"Hedwig is a terrible, terrible name for an owl."

"What? It's perfectly fine to me. Honestly, Athena is such a boring name for an owl."

"You do have a point, Harry."

"I'd say Minerva, but Professor McGonagall is called that too."

"How about Alberta then?"

In the end, they settled on Juno, for no other reason than to stop the argument.

\--

Come September 1st, Vernon had left the twins at King's Cross Station.

"Did Hagrid ever tell us how to get to Platform 9 and 3/4?"

"I don't think so."

A wafting conversation caught their ear, and they met the Weasleys, from straight-laced Percy, to the fun-loving twins, dirt-nosed Ron and little Ginny.

"Follow the red hair, shall we?"

"Dearest sister, your hair is red too."

"Bugger off, Harry. You know what I mean. Those people look like they know the way onto the platform."

"Red hair it is then."

\--

"Are you really the Potter twins?"

Harry gave a tired smile and lifted his fringe, while Rose gave the newcomer a timid little wave.

Instead of becoming awestruck like they thought he would, Ronald Weasley turned sombre and said, "I'm sorry about your parents. Mum told me they were good people."

This was news to them both. The Weasleys knew their parents? This warranted further enquiries.

But for now, they would have to learn about this strange new world, from this strange new boy.

"Please, have a seat. You can introduce us to the Wizarding World!"


	2. AN: Regarding new updates

AN: Hiya! Just writing this to let you know that I'm rewriting the first chapter, and to thank the few of you here for your support. Unfortunately, due to academic concerns, new chapters will not be uploaded until after the 16th of June.

Now, since ffn doesn't like purely AN chapters, here's a short bit that I wrote from a prompt on Reddit. Enjoy!

"The fourth Triwizard champion. Harry Potter."

"Harry, go."

*meanwhile, in Moody's quarters*

A trunk clunks open. The sneakoscope whir as a wooden, clawed foot is launched out of the opening.

"Free! Free!" screams Alastor Moody.

"Now, I'm going to stuff my foot up that dickhole's arse. Onwards we go!"

*in the Champions' Room*

Barty Crouch finished his explaination of the Goblet's deception. He smiled to himself, satisfied. Everything was going to plan.

*in the Great Hall*

"Piece of trash took my goddamn eye. God, I miss having depth perception."

"Would sir like Dobby to help you?"

"Good elf. Take me to Dumbledore."

*in the Champions' Room*

"Goodnight, children. Alastor, lead the--"

Dumbledore was cut off by a large crack and the appearance of a house elf and...

 **Another** Alastor Moody?

"Yargh!" yelled the newcomer. "I'm going to stuff my foot up your arse, Death Eater scum!"

Unfortunately for Barty Crouch Junior, Moody had lost all sense and depth perception. As a result, the foot was roughly stuffed into the wrong opening.

Barty Snr. was arrested, while his son was transported to St. Mungos to be examined.

"How did this get in there?"


End file.
